Stranded torsion bar for maintaining a printing plate on a printing cylinder

ABSTRACT

A printing plate tensioning device which affords adjustable, torsional forces to accommodate various types of printing plates, e.g., metal, plastic, etc. The device comprises a curved saddle adapted to be locked to a printing press, a saddle supporting the printing plate about its outer surface and having the general shape of a sector of a hollow cylinder having a leading edge and a trailing edge, a first securing element connected to the leading edge of the saddle to secure one end portion of the printing plate, a barrel mounted to the trailing edge of said saddle and spaced apart therefrom, and having a second securing means attached thereto for securing the other end portion of the printing plate, a stranded member situated within said barrel along its length, and being defined by a section of a multiplicity of closely spaced filaments, one end of the section coupled to said barrel and its other end being releasably connected to the saddle, and a restraining element associated with said barrel for restraining the rotation of said barrel while said stranded member is being rotated, whereby the stranded member imparts torsional tensioning force to the barrel when in a plate locked position.

1 [22] Filed:

United States Patent 1 Cerny et a1.

1 Nov. 25, 1975 1 STRANDED TORSION BAR FOR MAINTAINING A PRINTING PLATE ON A PRINTING CYLINDER [75] Inventors: Daryl D. Cerny, Greenville, Ohio;

Phillip R. Rodenberger, Muncie, Ind.

[73] Assignee: Ball Corporation, Muncie, Ind.

Feb. 14, 1974 [21] Appl. No.: 442,724

[56] References Cited UNITED STATES PATENTS 748,641 l/l904 Newell 160/306 1,016,511 2/1912 Mitchell I .1 51/367 1,651,924 12/1927 Lichtenstein. lO1/4l5.l 2,730,364 1/1956 Thomsen 101/409 X 2,767,653 10/1956 Babicz 101/409 3,332,346 7/1967 Luehrs I 10l/415.l 3,669,398 6/1972 Robinson... 248/373 3,766,857 10/1973 Schlatter 101/378 X FOREIGN PATENTS OR APPLICATIONS 475,597 7/1951 Canada 160/189 Primary Examiner-Edgar S. Burr Assistant ExaminerPaul J. Hirsch Attorney, Agent, or Firm-Gilbert E. Alberding [57] ABSTRACT A printing plate tensioning device which affords adjustable, torsional forces to accommodate various types of printing plates, e.g,., metal, plastic, etc. The device comprises a curved saddle adapted to be locked to a printing press, a saddle supporting the printing plate about its outer surface and having the general shape of a sector of a hollow cylinder having a leading edge and a trailing edge, a first securing element connected to the leading edge of the saddle to secure one end portion of the printing plate, a barrel mounted to the trailing edge of said saddle and spaced apart therefrom, and having, a second securing means attached thereto for securing the other end portion of the printing plate, a stranded member situated within said barrel along its length, and being defined by a section of a multiplicity of closely spaced filaments, one end of the section coupled to said barrel and its other end being releasably connected to the saddle, and a restraining element associated with said barrel for restraining the rotation of said barrel while said stranded member is being rotated, whereby the stranded member imparts torsional tensioning force to the barrel when in a plate locked position.

4 Claims, 7 Drawing Figures U. S. Patfint Nov.25, 1975 Sheet 1 of3 3,921,526

FIG. 2

US. Patent Nov. 25, 1975 Sheet20f3 3,921,526

STRANDED TORSION BAR FOR MAINTAINING A PRINTING PLATE ON A PRINTING CYLINDER BACKGROUND OF THE-INVENTION The present invention relates to printing presses and more particularly to a novel and improved means for securing and retaining printing plates on a printing cylinder. Specifically, this invention relates to an apparaplates have been developed, many of them combining other functions than clamping alone. The prior art mechanisms are often found to be complicated and expensive to manufacture, and maintenance and repair services of such devices have been involved requiring major dismantling operations and extended shutdown periods of the printing machines.

Various means of attaching plates to a support have been devised to assure that printing plates will not work loose on their support during printing or will be thrown off during high-speed operations, there has been no convenient device for quickly locking a printing plate upon a support and remain relatively fixed thereon during expansion of the printing plate which often occurs after the plate has gone through a number of revolutions during the printing operation. Some of the conventional means for locking the printing plates in position which have been used heretofore are various chemical bonding agents or adhesives and various bolting mechanisms. When plate expansion does occur under circumstances where conventional locking means have been employed, it has been found necessary to shut down the printing operation for making adjustments. The adjustment usually required is the removal of the saddle or cylinder and the realignment of the locking mechanisms. A number of recent developments have provided locking devices which hold a printing plate under resilient tension so that plate expansion can be readily compensated during the printing operation. Certain deficiencies are associated therewith. Generally, the devices providing resilient tension are inadequate to meet the pressures exerted by highspeed operations. Further, substantial modification of the cylinder or saddle is often required to provide for the tensioning mechanism. In such case, the mechanism is not adaptable for use on an existing press cylinder. Moreover, the prior art mechanism for tensioning printing plates often require springs which exert compression or tension forces upon various locking elements associated therewith. Although these prior devices are generally attached to a recess portion of a printing t-vlintler, they have limited accessibility due to the conventional design of most printing machines.

l3Rli':ll- DESCRIPTION OF THE INVENTION 'lln: present invention has for one of its objects the provision of a novel and improved plate securing means adapted to secure printing plates on the printing cylinders of n high-speed rotary newspaper press.

Another object of the instant invention is to provide a mechanism which exerts torsional forces in an extremely confined space to secure and offer sufficient (legit-t. of expansion for a printing plate during a printing operation.

Another object of this invention is to provide a mechanism for a printing plate which will allow a large amount of force to be applied. in a given and restricted space by use of a torsion mechanism associated therewith.

Another object of this invention is to provide for loading a printing plate under adequate lineal take-up allowance.

Other and further objects and advantages of the invention will be hereinafter described or will be apparent from the following description, and the novel features thereof will be defined in the appended claims.

According to the present invention, a mechanism is provided for locking and maintaining a printing plate to a saddle under continuous tension so that appropriate tension is maintained even during high-speed press operation. The mechanism for mounting the printing plate to a press comprises a curved saddle adapted to be locked to a printing press, said saddle supporting the printing plate about its outer surface and having the general shape of a sector of a hollow cylinder, said saddle having a leading edge and a trailing edge, a first securing means connected to the leading edge of said saddle to secure one end portion of the printing plate, a barrel mounted to the trailing edge of said saddle and spaced apart therefrom, said barrel having a second securing means attached thereto for securing the outer end portion of the printing plate. a stranded member situated within said barrel along its length, said stranded member being defined by a section of a multiplicity of closely spaced filaments, one end of the sect BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a vertical section of a printing press cylinder.

FIG. 2 illustrates a longitudinal view with cutaway portions of the stranded torsion bar described herein.

FIG. 3 illustrates a cutaway portion of the printing cylinder showing the printing plate in its lock-up position.

FIG. 4 illustrates a cutaway portion of the printing cylinder with the printing plate in its loading position.

FIG. 5 illustrates a preferredl locking means showing a cross sectional view when the locking means is in a plate loading position.

FIG. 6 illustrates the same preferred embodiment showing the position of said means in a plate lockup position.

FIG. 7 illustrates the preferred locking means at its full extended positon.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although it is understood that the subject device may accommodate a tubular printing press system, i.e., where there is a single saddle structure, the following description will deal with a printing press in which there is at least two saddle structures.

Referring now in detail to the illustrative embodiment of the invention, a printing cylinder 10 is provided and is adapted to receive and have secured to it at least two semi-cylindrical saddles 11 upon which is secured a printing plate 12 by means herein described. Plate 12 is preferrably formed near its leading and trailing edges, 14 and 13, respectively, with a plurality of openings 23 and a recess 22, which are preferrably axially aligned, and may be positioned a predetermined distance from the leading or trailing edge of the plate. The printing plates that are standard in the technology are provided with these cut out portions to accommodate the conventional saddle structure. FIG. 4 illustrates a printing plate 12 having a cutaway portion 22 and a number of openings 23 to accommodate conventional holding means defined by a number of pins 24.

In accordance with the instant invention, means are provided for securing the flexible printing plate 12 to the semi-cylindrical saddle through the use of a stranded torsion member 15. The member 15 is positioned at the trailing edge of the printing plate. The stranded torsion member 15 is illustrated in FIG. 2. The device comprises an outer cylindrical barrel l6 and a stranded member 17 situated within said barrel 16. The stranded member 17 is connected to a key 18 at one end of the barrel 16. The stranded member 17 comprises a multiplicity of filaments, which may be steel, copper, elastomers of polymeric material, or the like which are collectively combined along all or substantially most of the length of the barrel 16. The multiplicity of filaments have two terminal ends 19 and 20 which extend outwardly from the barrel 16. The terminal end 19 is defined by a cylindrical cap which retains the stranded filaments therein. The other end of the filaments is defined by a hexagonal cap member 20 which freely rotates within the barrel 16. The barrel 16 has affixed thereto a number of pins 24 which fall along the axial length of barrel 16. A restraining peg 26 is centrally located on barrel l6 and is positioned substantially at the opposite side with respect to the center pin 24.

The stranded torsion member 15 is attached to the saddle 11 by means of side plates 28. One of the side plates 28 has a circular aperture to rotatably accommodate cap 19 and the other side plate has an angular aperture to accommodate cap 20. The side plates 28 are affixed to the saddle by means of screws 29.

Although this invention has been described as having pins in the ends of the saddle 11 and in the barrel 16, several other attachment means may be substituted without changing the general features of the invention. Thus, slots may be provided to accommodate the printing plate. Thus, the printing plate may be slipped into the slot and then rotated into a locked printing position. Other suitable securing means may be utilized and are well known to those skilled in the art.

It is preferred that the stranded member be a bundle of wires. It is understood that the bundle of wires may be arranged in various configurations. One preferred configuration is one in which the filaments are arranged circumferentially. In the construction of the member, the bundle of filaments may be bonded together by means well-known in the art. Since the filaments in the center of the bundle are not stressed to the same extent as filaments on the outside of the bundle, and during angular displacement the outer filaments become tensioned to a greater extent than the inner filaments so that the outer filaments carry more of a load than the inner filaments. It is understood that the filaments may be arranged in any configuration, that is they may be twisted, roped, and intertwined. Further,

the filaments may be incapsulated or surrounded by a polymeric matrix for structural support. The terminal ends of the filamentsmay be bonded by conventional means such as soldering the ends of the filaments to a support. Further, the ends may be simply clamped mechanically.

The flexible printing plates which are conventional in the trade may be in the form of zinc plates, plastic plates, or other suitable material. With respect to zinc plates, it is generally found that a relatively high tensional force is required in the range of about 40 to about 60 lbs. per plate. On the other hand with respect to thin metal back plates or all plastic plates, a relatively lower requirement ranging from about 15 to 25 lbs. per plate.

The filaments which are preferrably employed in the subject invention are steel wires which may range in number from as many as of a 0.016 inch diameter wire bundle to about three strands of a 0.056 wire bundle. A preferred bundle configuration for the subject invention is in the range of about 20 to 30 strands and preferrably in a diameter of from about 0.020 inches to about 0.030 inch.

In operation, the standard torsion device 15 is inserted into the side plate having a circular internal opening. After the cap 19 is received into said opening the device is brought along side the saddle 11 and the restraining peg 26 is inserted into the recess 30. The side plate 28 having a hexagonal configuration is placed over cap 20 having a complimentary configuration and rotated in a clock-wise manner to tension the multiplicity of filament 17. Upon rotation of stranded member 17 the auxiliary pin engages the upper side wall 31 of slot 30 and is retained thereagainst. The side plate 28 is then affixed to the saddle 11 to provide the desired torque. This is best shown in FIG. 7. Upon rotating the central pin 24 by suitable means, the flexible printing plate 12 may be extended over and positioned upon the pins 24. The means employed to rotate the central pin 24 to a position for loading the printing plate is not shown but various devices such as pliers, etc., may be used to achieve this step.

The recess 22 is provided in the printing plate 12 to accommodate such devices for rotating the barrel 16 to a plate loading position. Upon release of the barrel a force is imparted to the printing plate to secure the plate to the saddle. Thus, a uniform force is exerted over the full extent of the printing plate 12.

Resort may be had to such modifications as to fall within the spirit of the invention and the scope of the appended claims.

Having thus fully described the invention, what is claimed and is described to be secured by Letters Patent is:

1. A device for mounting a flexible printing plate to a press, comprising:

a curved saddle adapted to be locked to a printing press, said saddle supporting the printing plate about its outer surface and having the general shape of a sector of a hollow cylinder, said saddle having a leading edge and a trailing edge,

a first securing means connected to the leading edge of said saddle to secure one end portion of the printing plate,

a barrel mounted to the trailing edge of said saddle and spaced apart therefrom, said barrel having a second securing means attached thereto for securing the other end portion of the printing plate,

a torsion member comprising a stranded member situated within said barrel along its length, said stranded member being defined by a section of a multiplicity of closely held filaments collectively combined in the form of a wire bundle, one end of the section fixed with respect to said barrel and rotatably mounted with respect to said saddle and its other end being rotatable relative to said barrel end being selectively rotatably connected to the saddle, and a restraining means associated with said barrel for restraining the rotation of said barrel in one direction while said stranded member is being rotated during pretensioning of said torsion member, said barrel being rotatable in the other direction 6 with said torsion member to allow securement of a plate to said barrel.

2. A device as recited in claim 1 wherein the first and second securing means comprise pins over which a flexible printing plate may be impaled.

3. A device as recited in claim 1 wherein said first and second securing means comprise slots into which the ends of a flexible printing plate may be inserted.

4. A device as recited in claim 1 wherein said other end of said stranded member is connected to said saddle by a side plate, said plate having an opening to accommodate said other end of the said stranded member. 

1. A device for mounting a flexible printing plate to a press, comprising: a curved saddle adapted to be locked to a printing press, said saddle supporting the printing plate about its outer surface and having the general shape of a sector of a hollow cylinder, said saddle having a leading edge and a trailing edge, a first securing means connected to the leading edge of said saddle to secure one end portion of the printing plate, a barrel mounted to the trailing edge of said saddle and spaced apart therefrom, said barrel having a second securing means attached thereto for securing the other end portion of the printing plate, a torsion member comprising a stranded member situated within said barrel along its length, said stranded member being defined by a section of a multiplicity of closely held filaments collectively combined in the form of a wire bundle, one end of the section fixed with respect to said barrel and rotatably mounted with respect to said saddle and its other end being rotatable relative to said barrel end being selectively rotatably connected to the saddle, and a restraining means associated with said barrel for restraining the rotation of said barrel iN one direction while said stranded member is being rotated during pretensioning of said torsion member, said barrel being rotatable in the other direction with said torsion member to allow securement of a plate to said barrel.
 2. A device as recited in claim 1 wherein the first and second securing means comprise pins over which a flexible printing plate may be impaled.
 3. A device as recited in claim 1 wherein said first and second securing means comprise slots into which the ends of a flexible printing plate may be inserted.
 4. A device as recited in claim 1 wherein said other end of said stranded member is connected to said saddle by a side plate, said plate having an opening to accommodate said other end of the said stranded member. 